I've written a little introductory article on using the Zeroconf protocol with Python. Zeroconf allows servers running on one machine to publish their existence to other machines on the local network; applications can then locate available servers.
The article is: http://www.amk.ca/python/zeroconf (Some people will have already seen this article on my weblog or on the daily Python-URL. The only change is that a new release of PyZeroconf has been made, and the text has been updated to mention this.) --amk -- http://mail.python.org/mailman/listinfo/python-list